The relationship between local structure and photo-Fenton catalytic ability of glasses and glass-ceramics prepared from Japanese slag

Local structure and the photo-Fenton reactivity of iron-containing glasses and glass-ceramics prepared from Japanese domestic waste slag were investigated. The largest rate constant (k) of (2.8 ± 0.08) × 10−2 min−1 was recorded for the methylene blue degradation test by using H2O2 with a heat-treated ‘model slag’. The 57Fe Mössbauer spectrum was composed of a paramagnetic doublet with isomer shift of 0.18 ± 0.01 mm s−1 attributed to distorted FeIIIO4 tetrahedra. These results indicate that the paramagnetic Fe3+ provided strong photo-Fenton catalytic ability, and that waste slag can thus be recycled as an effective visible-light activated photocatalyst

Membranes of benzene sulfonylated-polyphenylene oxide as affinity membranes for propylene and propane gases

105-112Modified membranes of poly (2,6-dimethyl-1,4-phenyleneoxide) (PPO) have been prepared by electrophilic sulfonylation using benzenesulfonyl chloride with 17% and 48% degrees of substitution (dsub). The prepared membranes of benzene sulfonylated PPO polymer (SO2-PPO) are used in the gas permeation studies of petrochemically important C3 hydrocarbons, propylene and propane. Pure gas permeation and 55:45 binary gas mixture separation has been studied at 30±2°C. The modified membrane with dsub of 17% show two-fold improvement in permeabilities for both gases with a minor decrease in the propylene/propane selectivities compared to the parent PPO. However, membrane with higher dsub (48%) is found to be brittle. Single gas equilibrium sorption studies show that with increase in dsub the gas solubility coefficients increases. The polymers are characterized using proton NMR, FTIR, WAXD and DSC studies for structure and property interpretations. Interchain distance (deff) obtained from WAXD and the fractional free volume (FFV) calculated using group contribution method decreases for the modified polymer. This indicates that the diffusion controlled permeation of gases is less significant after modification. Hence the study reveals that the SO2-PPO has greater affinity for the C3 hydrocarbons. The modified membrane has potential to separate hydrocarbons from other non-hydrocarbon gases like those present in refinery off-gas mixtures. </span

Mechanical properties of simultaneous interpenetrating polymer networks of castor oil based polyurethane and polystyrene

Castor oil and 4,4'-diphenyl methane diisocyanate based polyurethane (PU)-polystyrene (PS) simultaneous interpenetrating polymer networks (IPNs) were synthesized with various PU/PS ratios (100/0, 90/10, 80/20, 75/25, 60/40 and 50/50). Mechanical properties (tensile strength, % elongation, elastic modulus, wear resistance, tear resistance and Shore-A hardness) of the IPNs showed a significant improvement beyond a critical styrene level (25% by weight). However, % elongation at break showed a maximum at 40% styrene. PU/PS IPNs of a fixed styrene level with varying amounts of styrene crosslinking agent, divinyl benzene (DVB), were also synthesized. These materials showed a significant improvement in the mechanical properties with increasing concentration of DVB. The observed behaviour is explained on the basis of results from swelling and Soxhlet extraction studies